000
AXPZ20 KNHC 272133
TWDEP 

TROPICAL WEATHER DISCUSSION    
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC TUE JUL 27 2010

TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN
FROM THE EQUATOR TO 32N...EAST OF 140W.

BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
2115 UTC.

...ITCZ...
AXIS ALONG 10N86W TO 11N100W TO 09N110W TO 12N140W. SCATTERED 
MODERATE TO STRONG N OF 06N TO THE COASTS OF PANAMA AND COSTA 
RICA BETWEEN 80W AND 86W. SCATTERED MODERATE ISOLATED STRONG 
WITHIN 120 NM OF THE AXIS BETWEEN 97W AND 109W...AND WITHIN 180 
NM N OF THE AXIS BETWEEN 92W AND 95W. SCATTERED MODERATE WITHIN 
60 NM OF AXIS BETWEEN 115W AND 120W. 

...DISCUSSION...
LARGE AMPLITUDE UPPER LEVEL TROUGH EXTENDS FROM WELL N OF BASIN 
THROUGH 32N130W BECOMING SHEARED SW TO 23N140W. THIS TROUGH IS 
SHEARING OUT IN THE FACE OF A BROAD RIDGE WHICH EXTENDS FROM 
AN ANTICYCLONE CENTERED OVER SOUTHERN BAJA CALIFORNIA WWD THROUGH
23N125W TO 20N140W AND ANCHORED BY ANOTHER ANTICYCLONE WELL W OF 
THE AREA NEAR THE HAWAIIAN ISLANDS. NWP MODEL GUIDANCE REINFORCES
THE ANTICYCLONE/RIDGE AND FORCES THE TROUGH TO GRADUALLY RETREAT 
TO THE W AS RIDGE EXTENDS/BUILDS WWD. VERY DRY AND STABLE AIR 
MASS DUE TO MODERATE TO STRONG SUBSIDENCE IS NOTED N OF 18N W OF 
120W AND N OF 23N BETWEEN 115W AND 120W. MID TO UPPER LEVEL 
MOISTURE IS BEING ADVECTED TO THE W BY THE ANTICYCLONE NOTED 
ABOVE AND EXTENDS WWD S OF 18N TO 130W BY QUASI ZONAL EASTERLY
FLOW ALOFT. LACK OF LOW LEVEL FORCING OUTSIDE OF THE ITCZ IS 
HINDERING THE  DEVELOPMENT OF DEEP CONVECTION W OF 110W. 
WIDELY SCATTERED CONVECTION ASSOCIATED WITH A LOW LEVEL TROUGH
SOUTH OF THE GULF OF TEHUANTEPEC HAS DECREASED IN COVERAGE OVER 
THE PAST SEVERAL HOURS.

ELSEWHERE AT THE SURFACE...
A WEAK TROUGH...REMNANTS OF A TROPICAL WAVE...HAS ESSENTIALLY 
DISSIPATED SOUTH OF THE GULF OF TEHUANTEPEC. 

BROAD 1028 MB HIGH PRES CENTER WELL NW OF AREA NEAR 43N143W WITH 
AN ASSOCIATED RIDGE AXIS EXTENDING SE THROUGH 30N138W TO 
20N110W. THIS RIDGE EXTENDS JUST TO THE N OF A WEAK SURFACE 
TROUGH SITUATED TO THE N OF THE ITCZ EXTENDING FROM 18N112W TO 
12N115W. 

FRESH NW BREEZE HAS BEGUN TO FUNNEL DOWN ALONG W COAST OF BAJA 
CALIFORNIA PENINSULA FROM 24N TO 29N. IN ADDITION...PRES 
GRADIENT OVER FAR NW MEXICO EXPECTED TO EASE AS RIDGE DRIFTS W 
DIMINISHING THE PRESENT FRESH SE BREEZE IN GULF OF CALIFORNIA 
BELOW 20 KT WITHIN 24 HOURS.

FRESH E TO SE WINDS OVER S PAC CONTINUES TO GENERATE SOME LONG 
PERIOD SOUTHERLY CROSS EQUATORIAL SWELL WITH SEAS UP TO 9 FT 
ENCROACHING INTO E PAC WATERS S OF 10N AND E OF 95W. SEAS ARE 
EXPECTED TO PERSIST DURING NEXT 48 HOURS.

$$
COBB